Wall sliding with characterController against an edge

I'm trying to figure out how to make characterController slide along an edge as it would slide along a wall. I'm casting a ray starting forward (a little scaled back so the character can get closer to the edge) and shooting straight down:

 forwardRay = transform.position + transform.forward * 0.4f;
     RaycastHit hitInfo = default(RaycastHit);
     var raycast = Physics.Raycast(forwardRay, Vector3.down, out hitInfo, Mathf.Infinity, 1); 

Then, I find the floor point directly below the capsule:

 RaycastHit hitInfo1 = default(RaycastHit);
         var raycastl = Physics.Raycast(transform.position, Vector3.down, out hitInfo1, Mathf.Infinity, 1);

Finally, I fire a ray back from the point forward where there is no ground, but at the height of the point where there is ground beneath the player:

 ground = hitInfo1.point;
         RaycastHit hitInfo1 = default(RaycastHit);
         var raycast2 = Physics.Raycast(new Vector3(forwardRay.x, ground.y + -0.02f, forwardRay.z), new Vector3((-transform.forward).x, 0f, (-transform.forward).z), out hitInfo1, Mathf.Infinity, 1);

This gives me the a ray at the edge of where my capsule is trying to move: https://gfycat.com/costlyblushingdragonfly

I then take the point of where this ray hits, subtracted from my forwardRay and multiplied by my speed to give me an edge vector:

 edgeVector = (forwardRay - hitInfo2.point) * Mathf.Abs(currentSpeed) * 10f;

that I can subtract from my final movement:

 GetComponent<CharacterController>().Move((Quaternion.Euler(transform.eulerangles) * new Vector3(0f, gravity, currentSpeed) - edgeVector) * Time.deltatime);

Here's the full code I'm using to get the edge:

 void Update()
 {
  
     forwardRay = transform.position + transform.forward * 0.4f;
     RaycastHit hitInfo = default(RaycastHit);
     var raycast = Physics.Raycast(forwardRay, Vector3.down, out hitInfo, Mathf.Infinity, 1);
  
     if (raycast)
     {
         edgeVector = Vector3.zero;
     }
     else
     {
         RaycastHit hitInfo1 = default(RaycastHit);
         var raycastl = Physics.Raycast(transform.position, Vector3.down, out hitInfo1, Mathf.Infinity, 1);
  
     if (raycast1)
     {
         ground = hitInfo1.point;
         RaycastHit hitInfo1 = default(RaycastHit);
         var raycast2 = Physics.Raycast(new Vector3(forwardRay.x, ground.y + -0.02f, forwardRay.z), new Vector3((-forwardRay).x, 0f, (-forwardRay).z), out hitInfo1, Mathf.Infinity, 1);
  
         if (raycast2)
         {
             edgeVector = (forwardRay - hitInfo2.point) * Mathf.Abs(currentSpeed) * 10f;
         }
         }
         }
     }
 }

The issue I'm having now is that it works when everything starts at 0,0,0: https://gfycat.com/unselfishdevotedbird

But totally breaks when the capsule and floor is moved. This is with the floor and capsule moved along the x and z axis by 2: https://gfycat.com/envioustornafricanelephant

And by the time it gets to 9 on the x and z axis, the capsule just falls off: https://gfycat.com/impeccableinferiorfantail

I know this is because it's casting in the wrong direction, but when I correct it by casting directly backwards:

 var raycast2 = Physics.Raycast(new Vector3(forwardRay.x, ground.y + -0.02f, forwardRay.z), new Vector3((-transform.forward).x, Of, (-transform.forward).z), out hitInfol, Mathf.Infinity, 1);

the wall sliding effect breaks: https://gfycat.com/greentestyirukandjijellyfish

So, obviously all along the wall sliding effect was an accident, but I need to figure out either adjust my charactercontroller movement to slide against the correct vector, or find a relative vector direction I can use that would give the same effect.